<template>
  <div class="goods-image">
    <div v-show="show" class="large" :style="[{ backgroundImage: `url(${images[currIndex]})` },largerPosition]"></div>
    <div class="middle" ref="target">
      <img :src="images[currIndex]" alt="">
      <!-- 遮罩层 -->
      <div class="layer" v-show="show" :style="layerPosition"></div>
    </div>
    <ul class="small">
      <li v-for="(img, i) in images" :key="img" :class="{ active: i === currIndex }">
        <img @mouseenter="currIndex=i" :src="img" alt="">
      </li>
    </ul>
  </div>
</template>
<script setup>
import { useMouseInElement } from '@vueuse/core'
defineProps({
  images: {
    type: Array,
    default: () => []
  }
})
const currIndex = ref(0)
// 监听鼠标在元素内坐标
const target = ref(null)
// 1.是否显示遮罩和放大镜
const show = ref(false)
// 2.控制遮罩层的数据
const layerPosition = reactive({ // 该响应式数据将直接作为样式使用
  left: 0,
  top: 0
})
// 3.大图的背景定位数据，也要样式数据
const largerPosition = reactive({
  backgroundPositionX: 0,
  backgroundPositionY: 0
})
const { elementX, elementY, isOutside } = useMouseInElement(target)
watchEffect(() => {
  // 根据上面数据设置自己的数据
  show.value = !isOutside.value
  // 先将位置数据预先设置
  const position = { x: 0, y: 0 }
  if (elementX.value < 100) position.x = 0
  else if (elementX.value > 300) position.x = 200
  else position.x = elementX.value - 100

  if (elementY.value < 100) position.y = 0
  else if (elementY.value > 300) position.y = 200
  else position.y = elementY.value - 100
  // 给样式数据赋值
  layerPosition.left = position.x + 'px'
  layerPosition.top = position.y + 'px'
  largerPosition.backgroundPositionX = -2 * position.x + 'px'
  largerPosition.backgroundPositionY = -2 * position.y + 'px'
})
</script>
<style scoped lang="less">
.goods-image {
  width: 480px;
  height: 400px;
  position: relative;
  display: flex;
  z-index: 500;

  .large {
    position: absolute;
    top: 0;
    left: 412px;
    width: 400px;
    height: 400px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    background-repeat: no-repeat;
    background-size: 800px 800px; // 控制图片放大倍数
    background-color: #f8f8f8;
  }

  .middle {
    width: 400px;
    height: 400px;
    background: #f5f5f5;
    position: relative;
    cursor: move;

    .layer { // 遮罩层
      width: 200px;
      height: 200px;
      background: rgba(0, 0, 0, .2);
      left: 0;
      top: 0;
      position: absolute;
    }
  }

  .small {
    width: 80px;

    li {
      width: 68px;
      height: 68px;
      margin-left: 12px;
      margin-bottom: 15px;
      cursor: pointer;

      &:hover,
      &.active {
        border: 2px solid @xtxColor;
      }
    }
  }
}
</style>
